.red-big-center {
    color: greenyellow;
    background: #3f3b1f;
    width: 30%;
    height: 70px;
    margin: 10%;
    padding: 0;
    left: 10px;
    right: 0;
    position: absolute;

}

.red-big-center-onediv {
    font-size: 2em;
    text-align: center;
    padding: 15px;
    top: 29px;
}

.parent-bule {
    display: grid;
    place-items: center;
}

/*初始化， 取消页面的内外边距*/
* {
    padding: 0;
    margin: 0;
}

body {
    /*弹性布局 让页面元素垂直加水平居中*/
    display: flex;
    justify-content: center;
    align-items: center;
    /*让页面占屏总高*/
    height: 100vh;
    background-image: url('../picture/启明星使.jpg');
    background-size: cover;
    background-repeat: no-repeat

}

a {
    /*    相对定位*/
    position: relative;
    width: 400px;
    height: 100px;
    line-height: 100px;
    text-align: center;
    text-decoration: none;
    text-transform: uppercase;
    font-size: 24px;
    color: #fff;
    /*圆角*/
    border-radius: 35px;
    /*背景渐变色*/
    background-image: linear-gradient(to right, #03a9f4, #f441a5, #ffeb3b, #09a8f4);
    /*背景渐变色大小*/
    background-size: 400%;
    z-index: 1;
    margin: 100px;
}

/*发光效果*/
a::before {
    content: '';
    position: absolute;
    top: -5px;
    bottom: -5px;
    left: -5px;
    right: -5px;
    /*圆角*/
    border-radius: 35px;
    /*背景渐变色*/
    background-image: linear-gradient(to right, #03a9f4, #f441a5, #ffeb3b, #09a8f4);
    /*背景渐变色大小*/
    background-size: 400%;
    z-index: -1;
    /*设置模糊度*/
    filter: blur(20px);
}

a:hover {
    /*动画 名称 时间 infinite是无限次播放*/
    animation: sun 8s infinite;
}

a:hover::before {
    animation: sun 8s infinite;
}

@keyframes sun {
    100% {
        /*    背景位置*/
        background-position: -400% 0;
    }

}
